Known from DE 102 18 606 A1 is a potentiometric sensor, which includes a transducer and a digital data memory, wherein the data memory is connected permanently with the sensor. Stored in the data memory are process data or sensor data. The sensor communicates via an interface with a superordinated unit, e.g. a measurement transmitter or a cable. Via the interface, the sensor transmits measurement signals, which represent a pH-value or other measured value. Furthermore, data are read and written, respectively, from and to the data memory via the interface. Preferably, also the energy supply of the sensor occurs via the interface.
Known from DE 103 13 639 A1 is a comparable electrochemical sensor. The electrochemical sensor is, for example, an oxygen sensor. Corresponding sensors with inductive interface and corresponding technology are available from Endress+Hauser in various embodiments under the mark, MEMOSENS.
For the sake of completeness, it is noted that the field device of the invention is not limited to serving only for measuring and monitoring potentiometric or electrochemical, process variables. In principle, the invention is applicable in connection with any field devices, which measure a physical or chemical, process variable.
Problematic in the case of the known solution is that, in connection with the until now unique MEMOSENS technology, in the case of which the plug head and the plug coupling are coupled, or can be coupled, with one another via an inductive interface, in principle, all sensor elements or measurement transmitters of various manufacturers can be connected with the known plug head, or the known plug coupling. For example, any manufacturer of glass electrodes can connect its glass electrodes to the MEMOSENS products. The same is true for the measurement transmitters available from a number of manufacturers.